Christian rudolph



UNITED STATES IATENT OFFICR' CHRISTIAN RUDOLPH, OF OFFENBACH-ONTIIE-MAIN, GERMANY, ASSIGNOR TO K. .OEHLER, OF SAME PLACE.

TETRAZO DYE-STU FF.

' SPECIFICATION forming part of Letters Patent No. 396,293, dated. January 15, 1889.

Application filed September 3, 1888- Serial No. 284,466. (No specimens.)

.['0 all whom, it may concern: low-red, and in concentrated sulphuric acid Be it known that I, CHRISTIAN RUDOLPH, with a violet-red color. Being insoluble in a subject of the Emperor of Germany, and a water, it can be washed, and is then dissolved resident of Oftenbach-on-the-Main, Germany, (still in humid state) in ten pounds of ammo- 5 5 assignor to the firm of K. OEHLER, in the said nium of seventeen per cent. Add seven city of Oifenbach, have invented new and pounds of nitrite of soda and pour the whole useful Improvements in Coloringfilatter, of solution in muriatic acid cooled with ice to 0. which the following is a specificatlon. The intermediate compound precipitates My invention consists in the production of first in the shape of blackish flakes, which IO blue-black tetrazo dye-stuffs of the sulphochange color with the progressingdiazotation. acids of the amido-cresols. The latter are and appear finally pure red-brown. Arrived best produced by the well-known method of at this point of the process, the last step is Kolbe, (see Beilsieins Handlmch, second begun by pouring the diazotated compound edition, tome I, page 5-10,) by the nitrification into an alkaline solutionof thirty-three pounds I 5 of sulphureted cresols and following reducof R. salt and cooled with ice.

tion. They show almost the same reactions The dye-stuff is formed at once in the shape as the amidophenolsulpho-acids. (See Beilof a black precipitatenvhich is filtered, pressed, sie'ins Handbuch, second edition, tome I, page and dried. 541.) The dyestuffs form a black-brown powder 20 My way of proceeding is as follows: The with bronze luster, and are soluble in water sulpho-acids of the amido-cresols are diazowith blue-violet color. 3y the addition of tated in the wellknown manner and then ammonium the color of the solution changes combined with a naphthylamine. The combiinto pure blue. \Vith concentrated sulphuric nations thus obtained are again diazotatcd acid the dye-stuff shows a green reaction. 25 and then combined with the betanaphtholdi- These coloring-matters dye wool from violetsulpho-acid R. (see German Patent No. 3,229,) blue to blue-black, according to the strength.

to produce the new blue-black tetrazo dye- Having'thus described my invention and stuffs. the manner of employing the same, what I Example: 'lwenty-tlnee pounds of amidoclaim, and wish to secure to me by Letters o cresolsulphate of soda (which can derive either Patent ot' the United States of America, is from ortho-meta or para-cresol) and seven The tetrazo dye stuff herein described, pounds of nitrite of soda are dissolved in five which is produced from the sulpho-acids of hundred pounds of water and allowed to run the amidc-cresols by their combination with slowly into an excess of muriatic acid. The naphthylamine, the diazotation-ol the co1n- 3 5 diazo compound formed gives to the liquid a pound thus obtained and its combination with yellow-brown color. \Vhen the reaction is naphtholdisulpho-acid, and which is a blackfinished, a solution of twenty pounds of hybrown powder with a bronze luster having drochlorate of naphthylamine is added. The the following properties, viz: Forming when mixture is at the beginning clear, and troudissolved in water a blue-violet solution, 4o bles after a while by the separation of the which by the addition of ammonia is changed combination formed. At the ordinary temto pure blue, showing a green reaction with perature, and in a diluted solution, the reacconcentrated sulphuric acid, and dyeing wool tion goes on slowly for several days. By heatfrom violet-blue to bl ue-black, according to ing the mass to from 40 to 50 the formation its strength, substz-mtially as herein specified. 5 5 of the compound is accelerated. In testimony whereof I have signed my The reaction is considered to be completed name to this specification in the presence of when a sample filtered off gives no more pretwo subscribing witnesses.

cipitate after being a little heated or stand- CHRISTIAN RUDOLPH. ing for some time. lVitnesses: 50 The precipitate forms dark-green crystals, FRANZ HASSLACHER,

dissolving in ammonium with a brownish yel- CARL DURRSTEIN. 

